title: Fetal development of the vesico-ureteric junction, and immunohistochemistry of the ends of refluxing ureters.
abstract: There is still misunderstanding about the normal fetal development of the vesico-ureteric junction (VUJ), the region that is most important for preventing VUR. There is little information on the causes of primary VUR and on the mechanisms of maturation of refluxing ureteric endings. Some studies show that the ratio of the intravesical ureteric length to diameter is obviously lower than had been assumed. It is doubtful that the length and course of the intravesical ureter is the sole factor in preventing reflux, as previously reported. The intravesical part of refluxing ureters shows dysplasia, atrophy and architectural derangement of smooth muscle fibres. A pathologically increased matrix remodelling combined with deprivation of the intramural nerve supply has been confirmed. Consequently, symmetrical contraction of the distal ureteric smooth muscle coat, creating the active valve mechanism to prevent reflux, is impossible. We reviewed publications using Medline, with the keywords 'human fetal development', 'embryology', 'ureterovesical junction', relevant 'growth data', 'vesico-ureteric reflux', 'children', 'immunohistochemistry', 'extracellular matrix', and 'nerve supply', respectively. Priority was given to articles that correlated specific embryological findings and basic research on possible mechanisms to the genesis and maturation of the VUJ.
authors.affiliation: Department of Paediatric Urology, Medical University Innsbruck, Anichstr. 35, 6020 Innsbruck, Austria. christian.radmayr@uibk.ac.at
authors.forename: Christian
authors.initials: C
authors.lastname: Radmayr
authors.forename: Helga
authors.initials: H
authors.lastname: Fritsch
authors.forename: Christian
authors.initials: C
authors.lastname: Schwentner
authors.forename: Andreas
authors.initials: A
authors.lastname: Lunacek
authors.forename: Martina
authors.initials: M
authors.lastname: Deibl
authors.forename: Georg
authors.initials: G
authors.lastname: Bartsch
authors.forename: Josef
authors.initials: J
authors.lastname: Oswald